Time-delay relay system



y 20, 1952 R. M. LOMMEN 2,597,347

TIME-DELAY RELAY SYSTEM Original Filed Nov. 16, 1945 Patented May 20, 1952 TIME-DELAY RELAY SYSTEM Robert M. Lommen, Lombard, Ill., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Continuation of application Serial No. 629,051, November 16, 1945. This application February 15, 1951, Serial No."211,116

8 Claims. 1

The invention relates to timing systems and while not limited thereto is especially adapted for the timing of current supply to a welding transformer.

This application is a continuation of my application Serial No. 629,051, filed November 16, 1945, now abandoned.

An object of the invention is to provide a timing system which upon initiation of the flow of current in a translating circuit will maintain said flow for an adjustable period.

Another object is to provide a system which will supply, upon the operation of an initiating pilot device, a single current impulse of pre-adjustable duration.

Another object is to provide means for controlling the duration of a current impulse supplied to a translating circuit, and limiting such duration to a given preselected maximum interval.

Other objects and advantages will hereinafter appear.

The accompanying diagrammatic drawing is illustrative of an embodiment of the invention.

In the drawing,

Figure 1 is a diagram of connections for controlling welding impulses of given duration, while Fig. 2 is a modification of Fig. l, in which the duration of the welding impulses may be shortened at will.

Referrin to Fig. 1, L L represent the bus bars of an alternating current supply system. Connected to the line L is one terminal of the primary winding w of a welding transformer II) which also has a secondary winding lfl supplying current to a pair of welding electrodes II. A second terminal of the primary winding m is connected through the normally open contacts ll of an electromagnetic switch l2 to the line L The electromagnetic switch :2 is provided with an energizing winding I2. To initiate the power supply to the transformer l9, the system is provided with a normally open contact push button switch 13, one terminal of which is con nected to the line U. A second terminal of the push button switch 23 is connected to one terminal of a normally closed contact [4 of an electromagnetic relay M which is provided with an energizing winding ii A second terminal of the contact Ni is connected to one terminal of the winding lZ and the second terminal or" the Winding .iZ is connected to the line L 15 which is provided with an energizingwinding Connected in ,parallel with the contacts I3 are the normally open contacts IE- of an electromagnetic relay l5 connected in parallel with the winding I2 There is also connected across the lines L L but in series with contacts 13, the primary winding l6 of a transformer l5, said transformer having secondary windings l6 and 16. The winding Hi is adapted to supply power to a gaseous electron tube IT. The tube I! has a cathode Il an anode ll a control electrode I1 and a screen grid electrode l'l One terminal of the winding l6 is connected to the cathode Il while the second terminal is connected through the Winding W to the anode [1 The cathode I! is also connected to the screen grid electrode W A condenser I8 is connected in shunt with the winding [4 The control electrode l1 is connected through a resistor I9 in series with a condenser 20 to one terminal of the secondary winding 21 of a transformer 2|. The other terminal of the winding 2 l is connected to one terminal of the winding l5, while the other terminal of the winding 16 is connected to the cathode H The transformer 2| has a primary winding 2H connected across the lines L and L The condenser 20 is paralleled by an adjustable resistor 22 connected in series with a fixed resistor 23.

The system operates in the following manner: When the lines L and L are energized, the primary winding ll is energized and the voltage of the winding 2 l .is impressed between the cathode Il and the control electrode I! to charge the condenser 20. Due to the rectifying action of tube H the charge is such that it renders the control electrode l1 negative with respect to the cahtode Il When the push button switch I3 is depressed, the relay coils l5 and l2 are energized and current is supplied to transformer [0 while the relay [5 provides a maintaining circuit around the push button l3. The transformer winding [6 is also energized. This impresses a voltage between the cathode H and anode ll but the tube remains non-conducting by virtue of the negative potential of the control electrode ii. A potential is also induced in winding [6 which is slightly higher than and opposed to the potential induced in the Winding 21*; so that the potential which is impressed upon the condenser 20 is reduced to a very small alternating ripple voltage which causes the unidirectional charge of the condenser to slowly decay through the resistors 22 and 23.

When the voltage of the grid ll reaches the critical or firing voltage, conduction through the tube ll starts. The point of staring is more accurate by virtue of the alternating ripple voltage aforementioned. This energizes the relay winding I4 and the relay 14 opens the contacts H which in turn deenergizes relay l2 and interrupts the welding current. As stated, energization of winding 15 closes the contacts l5 which establishes a maintaining circuit in parallel with the push button l3 so that the push button l3 may be released without interrupting the energizing connections of the windings [2 and l5 and current will continue to be supplied to the transformer winding [6 Opening of contact M deenergizes relay l 5, thus opening the maintaining circuit for push button 13, so that if the latter is released relay [4 will be deenergized and restored to its normal position, thereby again closing the contact M Thereupon the system is in its initial condition for a second operation.

Referring now to Fig. 2, it will be observed that the relay I5 with its contact W is omitted. In this case the circuit of relay I2 is interrupted upon release of the push button l3, but if the push button 13 is held closed beyond the period of conduction of tube ll, that is, until after the relay M has responded, the welding current will not be reestablished until the push button switch I3 is released to return the relay M to its normal position and then the push button is depressed again. Thus, in either case, the maximum time durin which the welding current can flow upon each depression of the push button [3 is limited.

The condenser I8 is for the purpose of smoothing out the half Wave rectified current supplied to the winding M By adjusting the resistor 22 and/or the condenser 23 it is possible to adjust the time of operation within wide limits.

The gaseous tube I'l shown may be replaced by a suitable high vacuum tube and the screen grid ll may be omitted in either case without departure from the essence of the present invention. Other modifications within the scope of the invention will be apparent to those skilled in the art.

I claim:

1. In combination, an electric supply circuit, means to be supplied with a current impulse derived from said supply circuit, an electron tube having an auxiliary electrode for control, a condenser in circuit with said auxiliary electrode and the cathode of said tube and having a regulable discharge path, continuously acting means for subjecting said condenser to a charge by power derived from said supply circuit which condenser charge energizes said auxiliary electrode to a de gree blocking conduction of said tube, normally inactive means which when energized with electrical power affords neutralization of the condenser charging action of said continuously acting means and aifords a supply of power through the main conducting path of said tube, means for initiating flow of current from said supply circuit to said first mentioned means and said normally inactive means, and means responsive to power conduction of said tube for interrupting the fiow current to said first mentioned means.

2. In combination, an electric supply circuit, an electron tube having a cathode, an anode and a control electrode, a condenser in circuit with said cathode and said control electrode, a regulable discharge path connected acros said condenser, a transformer having its primary winding connected to said supply circuit and having a secondary winding in circuit with said condenser to charge the same by power derived from said supply circuit and subject said electrode to a potential blocking conduction of said tube, normally inactive means which when energized with electrical power affords neutralization of the condenser charging eifect of said transformer and affords a supply of power through the main conducting path of said tube, a translating device, means for initiating flow of current from said supply circuit to said translating device and said normally inactive means, and means responsive to power conduction of said tube for interrupting the flow of current to said translating device.

3. In combination, an electric supply circuit, an electron tube having a cathode, an anode and a control electrode, a condenser in circuit with said cathode and said control electrode, a regulable discharge path connected across said condenser, a first transformer having its primary winding connected to said supply circuit and having a secondary winding in circuit with said condenser to charge the same by power derived from said supply circuit and subject said electrode to a potential blocking conduction of said tube, a second transformer having a primary winding and secondary winding means in circuit with the secondary winding of said first transformer and the main conducting path of said tube for neutralizing the charging action of said first transformer and affording a source of power through the main conducting path of said tube upon energization of the primary winding, a translating device, means to initiate current flow from said supply circuit to the primary winding of said second transformer and to said translating device, and means responsive to power conduction of said tube for interrupting the flow of current to said translating device.

4. In combination, an electric supply circuit, an electron tube having a cathode, an anode and a control electrode, a condenser, a regulable discharge path connected across said condenser, a first transformer having its primary winding connected to said supply circuit and having a secondary winding in circuit with said cathode, said control electrode and said condenser to charge the latter and subject said control electrode to a potential which renders said tube nonconducting, a second transformer having a primary winding and two secondary windings, one of said secondary windings being in circuit with the secondary winding of said first transformer and being effective to neutralize the charging effect of said first transformer and the other of said secondary windings being in circuit with the anode and cathode of said tube to afford a source of power through the main discharge path of said tube whenever the primary winding is energized, a translating device, means for initiating current flow from said supply circuit through the primary winding of said second transformer and through said translating device, and means responsive to power conduction of said tube to terminate the flow of current through said translating device.

5. In combination, an electric supply circuit, an electron tube having a cathode, an anode and a control electrode, a condenser, a regulable discharge path connected across said condenser, a first transformer having a primary winding connected across said supply circuit and a secondary winding in circuit with said cathode, said control electrode and said condenser to charge the latter for subjecting said control electrode to a potential blocking conduction of said tube, a

second transformer having a primary winding and two secondary windin s one of which is in circuit with the secondary winding of said first transformer and being effective upon energization of the primaryiwinding to neutralize the condenser charging eifect of said first transformer, a translating device, electroresponsive means energizable to aiford supply of current derived from said supply circuit to said translating device, and means'for controlling the energization of said electroresponsive means andthe primary winding of said second transformer including a normally open switch operable to energize said electroresponsive means and the primary winding of said) second transformer with power from said supply circuit and further including an electromagnetic relay having an energizing winding connected in circuit with the main discharge path of said tube in series with the other secondary winding of said second transformer and being responsive to power conduction of said tube to effect deenergization of saidelectroresponsive means.

6. In a welding control system, the combination with an electroresponsive switch through the medium of whichwelding operations are controlled, of a control circuit for said switch comprising an electron tube having an auxiliary electrode for control, a condenser in circuit with said auxiliary electrode and the cathode of said tube and having a regulable discharge path, means to be continuously energized with electrical power to charge said condenser and subject said auxiliary electrode to a potential blocking conduction of said tube, normally inactive means which when energized with electrical power afiords neutralization of the condenser charging action of the first mentionedmeans and affords a supply of power through the main conducting path of said tube, and an energizing circuit for said switch and said normally inactive means including means operable to complete such circuit and further including means responsive to power conduction of said tube to deenergize said switch.

7. In a welding control system, the combination with an electroresponsive switch through the medium of which welding operations are controlled, of a control circuit for said switch comprising an electron tube having an auxiliary electrode for control,' a condenser in circuit with said auxiliary electrode and the cathode of said tube and having a regulable discharge path, means to be continuously energized with elec- .gize said switch and said normally inactive means.

8. The combination with a welding transformer and a source of electrical supply, of

means energizable to connect the primary winding of said transformer to said source, an electron tube having an auxiliary electrode for control, a condenser in circuit with said auxiliary electrode and the cathode of said tube and having a regulable discharge path, continuously acting means for subjecting said condenser to a charge by power derived from said source which condenser charge energizes said auxiliary electrode to a degree blocking conduction of said tube, normally inactive means which when energized with electrical power affords neutralization of the condenser charging action of said continuously acting means and afiords a supply of power through the main conducting path of said tube, means for initiating flow of current from said source to said first mentioned means and said normally inactive means, and means responsive to power conduction of said tube for interrupting the flow of current to said first mentioned means.

ROBERT M. LOMMEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,937,869 Brown Dec. 5, 1933 2,062,616 Stansbury Dec. 1, 1936 2,227,285 Stansbury Dec. 31, 1940 2,249,488 Nickle a- July 15, 1941 2,304,207 Richardson Dec. 8, 1942 2,337,905 Livingston Dec. 28, 1943 2,339,750 Bartholy Jan. 25, 1944 

